| **BUSINESS SEGMENTS - Narrative (Details) - USD ($) $ in Millions**                                                | 12 Months Ended |
|--------------------------------------------------------------------------------------------------------------------|-----------------|
||
| **Segment Reporting Information [Line Items]**                                                                     |            |   |   |
| Restructuring and related activities, term                                                                         | 3 years         |   |   |
| Revenue                                                                                                            | $ 19,419        | $ 17,062 | $ 17,814 |
| Amortization of intangible assets, debt premium, debt discount and debt issuance costs                             | 777             | 596 | 624 |
| LHX NeXt program                                                                                                   |            |   |   |
| **Segment Reporting Information [Line Items]**                                                                     |            |   |   |
| Restructuring charges                                                                                              | 25              |   |   |
| Restructuring liabilities                                                                                          | 4               |   |   |
| International                                                                                                      |            |   |   |
| **Segment Reporting Information [Line Items]**                                                                     |            |   |   |
| Revenue                                                                                                            | 1,882           | 1,689 | 1,580 |
| AR | International                                                                                                 |            |   |   |
| **Segment Reporting Information [Line Items]**                                                                     |            |   |   |
| Revenue                                                                                                            | 37              |   |   |
| SAS | International                                                                                                |            |   |   |
| **Segment Reporting Information [Line Items]**                                                                     |            |   |   |
| Revenue                                                                                                            | 874             | 712 | 704 |
| IMS | International                                                                                                |            |   |   |
| **Segment Reporting Information [Line Items]**                                                                     |            |   |   |
| Revenue                                                                                                            | 1,727           | 1,759 | 1,879 |
| CS | International                                                                                                 |            |   |   |
| **Segment Reporting Information [Line Items]**                                                                     |            |   |   |
| Revenue                                                                                                            | $ 1,535         | $ 1,437 | $ 1,232 |
| Revenue from Contract with Customer Benchmark | Government Contracts Concentration Risk | U.S. Government          |            |   |   |
| **Segment Reporting Information [Line Items]**                                                                     |            |   |   |
| Concentration risk percentage                                                                                      | 76.00%          | 74.00% | 75.00% |
| Revenue from Contract with Customer, Segment Benchmark | Product Concentration Risk | AR                           |            |   |   |
| **Segment Reporting Information [Line Items]**                                                                     |            |   |   |
| Concentration risk percentage                                                                                      | 29.00%          |   |   |
| Revenue from Contract with Customer, Segment Benchmark | Product Concentration Risk | SAS                          |            |   |   |
| **Segment Reporting Information [Line Items]**                                                                     |            |   |   |
| Concentration risk percentage                                                                                      | 28.00%          |   |   |
| Revenue from Contract with Customer, Segment Benchmark | Product Concentration Risk | IMS                          |            |   |   |
| **Segment Reporting Information [Line Items]**                                                                     |            |   |   |
| Concentration risk percentage                                                                                      | 38.00%          |   |   |
| Revenue from Contract with Customer, Segment Benchmark | Product Concentration Risk | CS                           |            |   |   |
| **Segment Reporting Information [Line Items]**                                                                     |            |   |   |
| Concentration risk percentage                                                                                      | 19.00%          |   |   |
| Revenue from Contract with Customer, Product and Service Benchmark | Geographic Concentration Risk | International |            |   |   |
| **Segment Reporting Information [Line Items]**                                                                     |            |   |   |
| Concentration risk percentage                                                                                      | 21.00%          | 23.00% | 22.00% |
| Revenue                                                                                                            | $ 4,200         | $ 3,900 | $ 3,900 |

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.
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| - Definition
Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.
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| - Definition
Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.
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| - Definition
Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.
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